Abstract: Unsegmented, continuous flow analysis, FIA, has been modified for automated measurement of the amounts of metal and metalloids with volatile hydrides. The sample is injected into a continuous carrier flow of acid, and upon reaction with sodium borhydride in a mixing coil, a gaseous hydride is generated which is blown with a gas flow to a detector, preferably an electrically heated quartz tube, and the atomic absorption is measured. The chemical interferences from other substances have been eliminated to a substantial degree by kinetic discrimination. Samples of about 1-100 nanograms can be determined at a rate of 180 samples per hour and with a detection limit in the sub-ng range.

Abstract: One or more components are determined in a sample by bringing said sample, which can be a liquid or a gas, into contact with a medium for adsorbing or taking up the components in question. A light beam is led via an optical cable through the medium containing the adsorbed or taken-up compound sought for, is reflected against a reflector material back through the medium, and the emitted light beam is detected. In enzymatic reactions, inter alia, a membrane can be utilized between sample solution and reagent, said membrane enabling the actual component to diffund through the membrane and react with enzyme, avoiding thereby the measurements to be disturbed by strong coloration and/or a high content of impurities in the sample solution. The membrane thereby serves as a reflector material for the light beam.

Abstract: Sample injection system for nonsegmented, continuous flow analysis comprising an inlet channel, an analyzer channel and a carrier stream channel connected in a confluence point, an aspirating pump in the analyzer channel, a carrier stream pump in the carrier stream channel with a higher capacity than the aspirating pump and an analyzer. In a first step prior to the sample injection, the carrier stream pump forwards carrier stream to the confluence point, the aspirating pump sucks carrier stream from the confluence point, at a lower rate than the carrier stream pump and an outflow of carrier stream drains through the inlet channel. In a second step, the carrier pump is stopped, the inlet end of the inlet channel is brought in contact with the sample solution, and the aspirating pump sucks sample into the inlet channel and the analyzer channel.

Abstract: A sample introduction system comprises a sampling circuit and a carrier stream circuit where the two circuits share a volumetric conduit which is at all times connected to and simultaneously opened to both sampling and carrier circuits. This system allows, by a controlled combination of hydrostatic and hydrodynamic forces, to create a well-defined sample zone within the volumetric circuit and then to transport this zone, in a well-reproduced manner, into a continuous flow analyzer where an assay of sample solution components may be performed quantitatively, if necessary even with the aid of chemical reactions, from the signal as provided by a flow-through detector.

Abstract: A process and an apparatus for flow extraction whereby a substance dissolved in a first solvent is extracted over to a second solvent which is insoluble in the first. The two solvents are brought together via two legs in a T-tube, and the mixture exits through the third leg, the cross-sectional areas of the legs being dimensioned to produce segmented flow with alternating plugs of the second and first solvents. The ratio between the cross-sectional areas of the tube legs for the first and second solvents is 2-8:1, preferably 4:1. Between the first and third legs carrying the confluent flows, the ratio between the cross-sectional areas thereof is reduced to 0.7-1.2:1, preferably 1:1, at a distance from the juncture which is 1-3 times the inner diameter of the third leg. The confluent flow is led through a spiral hose, producing a powerful extraction due to the counter-current turbulence.

Abstract: A continuous method of quantitatively determining slowly reacting compounds with the use of a single measuring cell, the sample being injected into a continuously flowing carrier solution which is already provided with, or simultaneously with the sample is provided with reagent to form a sample zone in the form of a reproducable gradient. Said sample zone is led into a measuring cell whereupon the flow is stopped by means of shunting the carrier flow, by stopping the pump, or by means of a valve. The reaction is allowed to take place in the measuring cell while a magnitude, characteristic for the reaction, is registered. The reaction speed can be detected from the incline of the obtained response curve and the amount of the sought-after compound is calculated. By means of setting the stop at a certain point in the concentration gradient curve and always selecting said point at the same time distance from the peak of the gradient curve during flow, a total reproducability of the analysis is ensured.

Abstract: Photometric cuvette for optical analysis of through-flowing medium, made as a thin and narrow transparent tube requiring minimum sample amounts. Light, substantially parallel to the tube length, is led obliquely into the tube through its wall, is reflected and led obliquely out through the tube wall to a detector. The angle of incidence is selected so that after entry, the light is totally reflected against the outer tube wall where the wall is in contact with surrounding atmosphere, the light being supplied essentially uniformly around the tube.

Abstract: A process and an apparatus for flow extraction whereby a substance dissolved in a first solvent is extracted over to a second solvent which is insoluble in the first. The two solvents are brought together via two legs in a T-tube, and the mixture exits through the third leg, the cross-sectional areas of the legs being dimensioned to produce segmented flow with alternating plugs of the second and first solvents. The ratio between the cross-sectional areas of the tube legs for the first and second solvents is 2-8:1, preferably 4:1. Between the first and third legs carrying the confluent flows, the ratio between the cross-sectional areas thereof is reduced to 0.7-1.2:1, preferably 1:1, at a distance from the juncture which is 1-3 times the inner diameter of the third leg. The confluent flow is led through a spiral hose, producing a powerful extraction due to the counter-current turbulence.

Abstract: A continuous method of quantitatively determining slowly reacting compounds with the use of a single measuring cell, the sample being injected into a continuously flowing carrier solution which is already provided with, or simultaneously with the sample is provided with reagent to form a sample zone in the form of a reproduceable gradient. Said sample zone is led into a measuring cell whereupon the flow is stopped by means of shunting the carrier flow, by stopping the pump, or by means of a valve. The reaction is allowed to take place in the measuring cell while a magnitude, characteristic for the reaction, is registered. The reaction speed can be detected from the incline of the obtained response curve and the amount of the sought-after compounds is calculated. By means of setting the stop at a certain point in the concentration gradient curve and always selecting said point at the same time distance from the peak of the gradient curve during flow, a total reproduceability of the analysis is ensured.

Abstract: Continuous flow analysis with an unobstructed, unsegmented carrier stream transporting a sample plug through a main conduit from a sample injection station to a flow-through detector. One or more reagents are injected in the sample plug on its way through the main conduit, the dispersion being controlled to optimize the conditions of chemical reaction. The reagents are added by being pumped in intermittently in merging streams, at least one of the solution delivering devices being activated and deactivated at pre-programmed time intervals during each sampling cycle. Each cycle is initiated by injecting the sample solution at the sample injection station. The solution delivering devices can have various pumping rates and at least one pump may be an automatic burette. The delivery is controlled by a timer or microcomputer, and the transport of solution can be momentarily stopped before the sample plug enters or while it is inside the flow-through detector.

Abstract: Method and device for continuous flow-through analysis with a non-segmented laminar carrier flow, to which reagents are added at programmable intervals. The programming can be done by switching in various loops with valves, interchangeable connections or by composing the apparatus of different prefabricated modules to produce the desired reaction conditions.

Abstract: A method and an apparatus for instantaneously determining ions in a carrier solution by means of leading it into a very thin continuous layer over the sensitive surface of an ion-selective electrode in a measuring cell and, from said measuring cell, on to a reservoir having a reference electrode so that the potential difference between the electrodes in the measuring cell can be continuously registered. The apparatus consists of a circuit having an inlet conduit, a pump, a sample addition apparatus, a loop, the measuring cell and a conduit via the pump to an outlet. The liquid level in the measuring cell is held constant, the ion-selective electrode being arranged above the liquid level and the reference electrode being immersed in the solution.

Abstract: Method and device for continuous flow-through analysis with a non-segmented laminar carrier flow, to which reagents are added at programmable intervals. The programming can be done by switching in various loops with valves, interchangeable connections or by composing the apparatus of different prefabricated modules to produce the desired reaction conditions.

Abstract: A method and an apparatus for supplying samples to a flowing continuous carrier solution for automatic analysis whereby a measured sampling conduit with a predetermined length and volume is alternately coupled to an intake conduit for the sample and the path of the flowing carrier solution. The sample circuit includes a sample container, an intake tube, the sample conduit valves and a pump, and the carrier flow circuit includes an inlet tube, a pump, a conduit, valves, a shunt conduit, an outlet conduit and an outlet, and by means of the valves, the sampling conduit is connected into and out of the carrier flow circuit parallel to the shunt conduit.

Abstract: The present invention relates to an electrode for measuring the nitrate concentration in aqueous solutions. The electrode consists of a container with an internal reference system and a membrane which is a combination of an organic nitrate sensor phase of a quaternary ammonium salt as electroactive material, an organophilic, hydrophobic solvent for the quaternary ammonium salt with substantial viscosity and polyvinyl chloride or polyurethane as non-porous material. The quaternary ammonium salt is chosen from the group consisting of: tetraoctyl ammonium nitrate, tetranonyl ammonium nitrate, tetradecyl ammonium nitrate, tetraundecyl ammonium nitrate, tetradodecyl ammonium nitrate, tetratridecyl ammonium nitrate and tetratetradecyl ammonium nitrate; and the solvent consists of dialkylphthalate or a dialkyladipate of a solubility parameter of 9 .+-. 2 (cal/cm.sup.3).sup.1/2.